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This is something of a prequel to The Engines of God where we see Priscilla Hutchins’ early days after getting pilots license for taking the big FTL interstellars out into the void. A lot of her early days are the frustration of not being able to get a steady job as a pilot, especially after she blew off one such job over an ethical issue. She still gets a little work here and there, but mostly she’s parked at a desk.

But it’s also the story of one of her instructors, Jake Loomis, and his flirtation with retirement. After a frightening brush with death, he decided he was done, but the business of interstellar flight was not quite done with him. So he kept getting pulled back in, “just for one more flight”. Ultimately the decision on whether or not he was going to retire was made by someone else.

While it was not as satisfying as a sequel to Cauldron would have been, it was fun to see Hutch back when she was still merely Priscilla, and to see how she earned her nickname in the first place. If you’re a fan of the Academy series, definitely check it out.

This is the sixth and final installment of my series on the different flavors of FTL. We’ve warped through hyperspace and jumped through wormholes… or something like that. To clear it up, here’s a summary table showing how these various flavors stack up on the criteria I used:

Clearly, that’s a simplification of several simplifications, but in reducing the various drive features to simple yes/no pairs, it highlights a couple of things. First, not all of the options are represented. What if you took something like warp drive and changed the FTL-FTL box to no? What would that look like if FTL ships could no longer interact? Is it that they cannot see each other? Or maybe they only see each other long after they’ve passed? Maybe they have FTL drives but not FTL sensors?

For another example, what if we put a “yes” in the FTL-Navigation box for wormholes? Maybe instead of simple point-to-point tubes, we’re actually cruising through a complex network of junctions and connectors. Maybe our expected Sol-to-Rigel trip is merely the result of taking all the default options at every junction? What if we could alter course at key junction points and end up somewhere entirely different? What if that kind of exploration can only be done by trial and fatal error?

The second thing I notice with such a table reduction is that there are very different ways to expand these choices into the story mechanics of the drive system. Consider that wormholes and jump drives have almost identical table entries, i.e. Rarely or No across most of the table. Yet these two FTL systems have very different feels to their stories.

Similarly, even staying within a single system can give you FTL drives that end up looking quite different in the actual stories. Consider warp drive. We’re all familiar with how it works in Star Trek. We tear across the universe, warping space and manipulating subspace fields and so on. In my space opera universe of the Hudson Confederacy, ships are using tachyon drives, essentially throwing up ephemeral sails to catch the tachyon wind and yank them up to FTL speeds. The mechanism looks completely different, yet functionally, my tachyon sails are just another warp drive. But my navigators don’t worry about subspace interference. Instead, they worry about shifting winds and tachyon storms.

Furthermore, it’s also an over-simplification to think that a story must use only one flavor of FTL. Many combine them. For example, the Honor Harrington series by David Weber uses a mix of hyperspace and wormholes. That is, while most travel occurs via hyperspace, one planetary system hosts the intersection point of several long-distance wormholes, giving them a huge strategic advantage both for shipping and war. Similarly, some of the later Star Trek series (TNG, DS9, and Voyager) added rare wormholes on top of their trusty warp drive fleet.

So, did I skip a flavor? Probably. There’s a lot of SF out there. Some of those FTL systems may indeed be fundamentally different, but I suspect that a lot of them will boil down to being one of these four with different names and different hand-waving for the so-called science.

But the most important thing for all of them is to get your characters from here to there before they grow old and die. And once there, they can try to write a letter home, which brings up the matter of FTL communication, but that’s a subject for some future series of articles. With luck, I’ll get to that before we reach Sirius.

This is the fifth installment in my series on the different flavors of FTL, and this week we’re jumping into… well, jumps. A jump is essentially teleportation over interstellar distances. You set your destination coordinates, hit the switch, and then you’re at the destination. In some stories, these jumps are instantaneous. In others, the jump takes time while you exist in some transitory null-space. That second variation might sound a lot like hyperspace, but the distinction between jumps and hyperspace are in the details.

One thing about jumping, though, is that the terminology is much sloppier than for other flavors. For example, the Dune universe used jumping, though they didn’t call it that. It was “folding space”, but it was functionally the same kind of interstellar teleportation that I’m describing here. Star Wars muddies the water further by talking about “jumping through hyperspace”, making it unclear which of the two flavors they’re using. This flavor is the furthest from known physics, so it’s understandable that it has the most hand-waving and distracting terms.

FTL-to-FTL Interactions: There are none. If the jump is instant, there is simply no time, but if even it takes a few days or weeks, the ship is not in any kind of recognizable space. You can’t see other ships, so you can’t interact with them.

FTL-to-sublight interactions: There are none. Again, if it’s instantaneous, there’s no time for such interactions, and even if it takes time, your ship is completely cut off from the rest of Einsteinian space.

Relativistic effects: If the jump is instant, there are one. If it takes time, I have typically seen it take the same amount of time on ship as it did in regular space. However, I don’t see this time match-up as a hard rule for this flavor of FTL.

In-FTL Navigation: There is none. All of your navigation choices were set before the jump. After that, you are simply waiting to land. This is probably the biggest distinction between jumps and the hyperspace flavor. Hyperspace typically allows at least some kind of in-FTL navigation, even if it’s merely to stop short and drop back to normal space.

Speed Differential: Yes, there can be speed differences but not in the normal sense. After all, my instant jump cannot be any faster than your instant jump, but it is possible for my jump to be of a greater distance than yours. I jumped to Sirius in one jump, but you require four shorter jumps. That speed differential is a fairly common one in both fiction and space-based RPGs.

Another speed differential with jumping can be in the time it takes to figure out all those jump coordinates. This is less about the drive itself and more about navigational sensors and computation power, but it still impacts the overall speed of a series of jumps strung together. Similarly, it can take time to refuel or recharge the jump drives. So, not only do these jump delays allow two similarly-rated ships to have different overall speeds, but they further penalize any ship that has to do a series of shorter jumps.

Furthermore, jump accuracy makes a big difference in the final planet-to-planet travel times. Does your jump drop you out at the edge of the star system? In the neighborhood of the planet? Or can you plop yourself down in the atmosphere on a landing path to the starport? The further out you are, the longer you’ll spend travelling at sublight speeds to finish off the journey. Similarly, some jump systems don’t work well in gravitational fields, so it’s necessary to travel a ways out before making your jump in the first place. Put those together, and drive accuracy and stability can add days or weeks to your journey.

Now, for those jumps that actually do take time, we get into speed differences that are much more familiar. How long does a jump take? Is it the same for all jumps? Does it get longer the further you go? Maybe some ships can jump five light years in a day while others take a week. This kind of variation is fairly rare in stories I’ve seen, but I would not say it’s disallowed by the general flavor of jumps. It’s just another tweak.

Malfunctions: These tend to be either errors of navigation or fatal disasters. Sloppy navigation could be from miscalculating those jump coordinates, but they could just as easily come from some mechanical failure in the jump drive itself. I can see the jump-drive equivalent of Scotty shouting to the bridge, “Aye, her core filters are as twisted as the Admiral’s knickers!” Still, the worst that has happened is that you ended up somewhere other than where you meant to land, and space is 99.999… some more 9’s … 99% empty space. Very likely, you won’t have landed inside anything nasty.

On the other hand, if “her core filters” are as twisted as Scotty says, they might just blow up when you hit the switch, especially if you’re too close to a planet, moving too fast, or anything else that makes a jump tricky. Who knows what would cause it, but when enough energy to teleport the ship five or ten light years goes awry, it’s not a healthy place to be.

And finally, there’s the possibility of jumping but never landing. These ships get lost in that transitory null-space, and we never hear from them again. Or do we? I’ve seen a few tales of the Flying Dutchman’s space cousin, and even one where they managed to recover them.

Special traits: A common feature I’ve see with jump drives is that they are reserved for larger ships, not little one-man fighters. This isn’t universal, but it’s common enough to note. Another feature I’ve seen crop up is the idea of jump points, i.e. fixed points in space where the local conditions are ideal for a jump. Those fixed points can add to the fun of space opera because they make space suddenly small again. The star system might be billions of kilometers across, but there are only four usable jump points. If you’re defending against an invasion or hunting unsuspecting merchants, those are the places you want to stake out.

That’s the end of the flavors. Tune in next week for a recap, some comparisons, and ideas that could point to as-yet-unsampled flavors.

This is the fourth in my series on various flavors of Faster Than Light (FTL) travel, and today I’m dropping into wormholes. The basic idea of a wormhole is that it’s a shortcut between two points. Usually they are fixed points, but there’s some variation on that. Sometimes they are done as predefined shortcuts through some alternate parallel space, and other times they are special tunnels through our own space.

In most cases, they are fairly permanent and independent of the ships traversing them. Thus, ships that have only sublight capabilities are now about to cross vast interstellar distances just by popping through these wormholes, just like a pedestrian can cross town quickly by taking the subway.

FTL-to-FTL interactions: These are almost nonexistent. The only interactions you might have are with other ships (or beings) that are in the same wormhole with you. Plus, wormhole trips are usually presented as being fairly short, so the opportunities for interaction would be fleeting.

FTL-to-sublight interactions: There are none. At least, that’s how I typically see it done. The wormhole is completely cut off from the rest of the universe. At best, there might be some communication with stations near either end of the wormhole.

Relativistic effects: Typically, there are none. Sometimes the transits are essentially instant, like walking through a doorway. Other times, they last seconds to hours, but it’s generally presented as time flowing tick by tick along with a stationary timeframe.

However, I know of one wormhole setup where the wormhole is a tubular region of space where time flows thousands of times faster than normal, thus making the speed of light in that region thousands of times faster. Ships passing through this make up for the time-scale by travelling at relativistic speeds, thus slowing their internal time by a similar factor to the external speed increase. Thus, they make a multi-year journey in a few minutes according to their own clocks and quite possibly a few minutes according to our clocks as well. In that setup, however, there is no guarantee of an absolute matchup between the ship clocks and the stationary clocks, so there would be some variation from one wormhole to another, and sometimes even from one trip to another on the same wormhole.

In-FTL Navigation: Nope, sorry. You don’t get to steer the train. You can’t even pull the emergency brake. And no hopping out the back either. You stay on it until it dumps you out the other end. Do not pass Rigel. Do not collect two hundred quatloos. Your best bet is to hope that there are other wormholes near the end of this one so that you can exercise at least a little choice.

Speed Differential: In all the wormhole systems I’ve seen, the ships within the wormhole all travelled through it at the same speed. Or if there was any speed variation, it was not under the control of the ships themselves. They were merely being swept along by currents of different speed. Of course, there’s no guarantee that all wormholes move you along at the same speed.

Malfunctions: All the breakdowns I’ve seen with wormholes have been with the wormholes themselves. Either they collapsed or became untethered at one end. Typically, the worst that happens to you is that you’re stuck at the wrong end of a wormhole. Then again, I’d hate to be inside one when it collapsed.

Special traits: Wormholes have several interesting traits in the story-telling sense. The first is that they are often pre-existing objects outside the control of the characters using them. Maybe they’re naturally occurring phenomena, or maybe they were built by “the ancients”. Or maybe, like the subways, they were built by the government, and we peons have to live with them as they are. They key here is that it’s no longer a space travel system where we get to pick out our destination and sail on through the night. Instead, there are a handful of destinations to pick from, and if that’s not where we want to go, that’s just too bad.

The second interesting thing about wormholes is what they do to the Euclidean topology of space. I’m not referring to some freaky space warping around the wormhole entrance. Rather, I mean that Rigel is now 500 million kilometers away rather than 900 light years, because there’s a wormhole to take us there. Meanwhile, our next door neighbor Proxima is still 4.24 light years away because it has no wormhole. Yet another nearby star Sirius is now only 2.1 billion kilometers away (rather than 8.6 light years) because we can get to it via a series of wormholes, i.e. first Rigel, then to Polaris, Antares, Deneb, and finally Sirius. (Don’t get lost at Deneb – it’s a bad neighborhood.)

And finally, if the wormholes are not strictly ignorant carriers of traffic, but instead, intelligent agents of control, then those first two factors can make for some very interesting situations. Imagine being able to control all commerce, traffic, even information flow between these distant stellar islands, simply by deciding which ships will complete their journey, which worlds to cut off, or which radio transmissions to shunt aside. Now start thinking about it from the point of view of we peons not realizing that the wormholes are under intelligent control, and let your space-opera paranoia turn all the way up to Eleven.

But one last bit on wormholes. Like the warp drive, these might be possible if not actually feasible. What we call a wormhole is remarkably similar to a prediction of General Relativity, known more properly as a Einstein-Rosen Bridge. However, since our best theoretical examples of such wormholes are tied up with black holes, this still has a long way to go to before we can turn it into the green-line express from Sol to Rigel.

This is the third in my series on different flavors of Faster Than Light (FTL) travel, and today I’m taking a look at hyperspace. The general idea here is that there is a separate space, parallel to our own, that allows for shorter travel between two points. It’s no longer four light years to Proxima. Instead, you transition over to hyperspace, travel a hundred thousand kilometers, and drop back into normal space at Proxima.

Generally, hyperspace is considered to be as Euclidean as normal space (which is not always truly Euclidean) and is scaled linearly with normal space. That’s the $5 way of saying that if you go twice as far in hypespace, you’ll go twice as far in normal space and in the direction you would have expected.

The only tricky thing about hyperspace is getting between normal space and hyperspace. In some stories, your ship can contain the necessary equipment to open a transition point. In other tales, it requires a gate in normal space to open that transition point. But once you’re over in hyperspace, it’s just a matter of throttling up or sailing away.

Let’s see how the details break out.

FTL-to-FTL interactions: This varies. In some stories, hyperspace is a chaotic or void space that is completely incomprehensible, so you cannot interact with other ships even if they were supposed to be flying formation with you. In other tales, hyperspace is pretty much just like normal space but with better graphics. In those cases, you can fly around, talk to other ships, and even shoot at them. Of course, there’s room to play around between those two extremes such as limiting communication range due to “hyperspace flux” or the likes.

FTL-to-sublight interactions: Usually there are no interactions here. You are in a truly separate space. At best there is a level of communication, but that is typically done via fixed points like gates. However, I have seen a couple of odd exceptions to this rule, typically where something unusual in normal space (such as a supernova or black hole) will cause a disturbance in hyperspace.

Relativistic effects: Generally there are none. The ships aren’t typically travelling very fast in hyperspace. It’s just that the distance there is shorter. Either that, or there is simply no special relativity in hyperspace. However, I have seen an odd time variation in some of C.J. Cherryh’s stories where mental processes continue on at a normal pace while other biological processes slow down. This allows frequent travelers to have a mental age of 40 while still appearing to be only 30.

In-FTL Navigation: This can vary, but there is almost always some. At the very least, ships travelling through hyperspace have the option of dropping back to normal space early, short of their destination. Course changes might require such a transition back to normal space, but there is that option. However, in most cases, hyperspace seems to allow as much navigational flexibility as the warp drive, complete with screeching turns and barrel rolls. Still, one limitation on this is the fixed points of gates. If you can only transition via the gates, then all the zigs and zags of your pilot won’t change the fact that you really only have a handful of destinations.

Speed Differential: Again, there typically is speed differential in hyperspace, typically achieved simply by travelling faster or slower within hyperspace. Sometimes, though, I have seen it done with multiple parallel spaces with different speed limits with them, e.g. hyperspace-A allows an effective 10-to-1 speed boost, while hyperspace-B gives 1000-to-1. However, I have seen a few cases (notably most of Jack McDevitt’s Omega Cloud series) where all ships travel through hyperspace at the same rate, since that is believed to be a fundamental property of hyperspace.

Malfunctions: These can suck. The most common malfunction is with your ability to transition to and from hyperspace. If you end up stuck in normal space, you’re just like the folks with the busted warp-drive, sticking your thumbs out in hopes of rescue. Except, of course, if you’re out in the middle of interstellar space, there won’t be any warp-drive ships careening past to see you. Instead, they’ll all be passing by unseen in hyperspace. Even worse is when you get stuck in hyperspace. Unless you can get to a gate to transition back, you’re left to the mercy of whatever monsters the author has left lurking in the dark corners of this alternate reality. Most often, those ships will simply disappear like the sailing ships of old, leaving only grieving widows and frustrated insurance adjusters.

Special traits: This is a nice dodge around relativity’s limits that doesn’t require much hand-waving with dubious physics. About the only big decision to make is whether or not ships can generate their own transition points or if some or all of them require a system of gates.

This is the second in my series on the different flavors of Faster Than Light (FTL) travel, and today I’ll be looking at the warp drive. The ideas for warp drive predate Star Trek, and they weren’t always called by that name, but Captain Kirk and the Enterprise are the iconic example of the warp drive. With a few words of technobabble, the universal speed limit is suddenly gone.

Yes, they paid lip service with the distinction between impulse drives and the warp drive, and over the years, they’ve filled our heads with all the technical details of subspace fields, warp bubbles, and such, but the basic result is that we are no longer bound by the upper limit of lightspeed. Let’s look at how some of the details shake out.

FTL-to-FTL interactions: Two ships travelling at warp speed can interact. That seems pretty universal. They can travel together, see each other coming, even take pot shots as they fly past. Sometimes there are a few restrictions, but they’re usually more of the nature of “that’s never been attempted at this speed!” In other words, they’re dramatic challenges for the engineer, not fundamental limitations on the physics.

FTL-to-sublight interactions: Yes, you can see the planet coming, and it can see you. You can steer around it and come back in for a strafing run. Stories with warp drive usually ignore the fact that you can’t literally see something coming at you faster than light with vague talk of “long-range sensors”.

Relativistic effects: Warp drives almost never deal with relativity. I think a lot of this is that once having dispensed with Einstein’s limits, they would rather not bring up real physics again. However, I have seen one or two instances of mild relativistic effects with warp drives. Kube-McDowell’s Trigon Disunity trilogy had a drive that ultimately moved the ship faster than light via some tricks of warped space, but the occupants were also travelling at relativistic speeds within that warped space. Thus, they experienced less than half the elapsed time as their Earthbound friends.

In-FTL Navigation: Warp-drive ships generally have no problem turning to starboard at faster than light speeds. Since we’re now pretending there’s nothing special about the speed of light and imagining ourselves in space-going navy vessels, there is no reason to suspect otherwise.

Speed Differential: Yes, the Joneses have a faster warp drive than you do. After all, if there is no longer an upper limit on speed, someone is always going to be at least little faster than you. Of course, since speed variation is possible, this also means you don’t have to be traveling at your maximum speed all the time. You can save warp 9 for the really dramatic moments.

Malfunctions: Whether it’s something as minor as a crack in the dilithium crystals or an ejected warp core, you’re not necessarily dead when things go wrong with your warp drive. Most of the time, you’re simply restricted to sublight travel again as Einstein takes a brief rest from spinning in his grave. Of course, many faults can be repaired, and you can get moving again. Failing that, you just have to stick out your warp thumb and wait for rescue.

Special traits: For storytelling, this is probably the easiest and to write and the simplest to grasp. It essentially ignores relativity and removes the problem of interstellar distances from the story. Rigel-4 is no longer hundreds of light-years away. It’s merely on the other side of the pond, so climb aboard the newest ship from the White Star Lines and have a safe… er… at least a short voyage.

But ironically, this flagrant slap in the face to physics is starting to look like it just might, maybe, theoretically be almost possible. In 1994, Miguel Alcubierre proposed a way of changing the shape of space around us, shrinking it in the direction we wanted to travel and expanding it in the direction behind us. It requires some pretty crazy technology, the science for which is still pure speculation, but after about twenty years, it has a few people seriously considering it as a matter for research. How seriously? Apparently NASA is spending some of its precious half-pennies on it. It might not be much more than a publicity stunt, but there’s always that outside chance that it might be something huge.

I don’t know which came first, the fictional accomplishment of travelling faster than light or Einstein’s prohibition against it, but one thing is certain, fictional FTL travel is here to stay. The genre of space opera almost requires it, and it has become a convenient cheat for telling stories over vast distances while still keeping them within our grasp.

This is the first of a six part series on the various flavors of FTL travel. Specifically, I’ll be breaking down the various forms of FTL travel and looking at how they work. I won’t be digging into the technobabble of fictional engineering manuals. Instead, I’ll be taking a look at how they work it story terms, i.e. what they allow, what problems they present, and so on.

Specifically, I’ll be examining each of them under these criteria:

Does it allow for FTL-to-FTL interactions? When you’re on your way from Earth to Rigel-4, can you run into another ship? Can you talk with them? Can you get into a fight with them? Or does this particular brand of FTL prevent those FTL ships from passing in the night?

Does it allow for FTL-to-sublight interactions? This is similar to but distinct from the first question. If you pass some planet along the way, can you see it? Can you make an FTL strafing run against some unsuspecting target? Or can they somehow see you coming?

Do you still have any relativistic effects? We might be mooning Einstein as we blow past at warp 5, but it might be possible to have some strange time dilation effects in place. Maybe you still age a little slower? Or faster? Or is it random?

Does it allow for in-FTL navigation? Do you set your destination and then trust to luck, or are you keeping one hand on the wheel at all times? If you find out that you’ve made a wrong turn, can you fix it, or do you simply have to wait until you get to other side?

Is all FTL the same speed? Does this particular FTL allow for some ships to be faster than others? Can you chase someone and catch up? Can you outdistance your pursuer? Or are we all on the same train?

What goes wrong? No mode of travel is without the occasional flat tire or torn wing. When your FTL engine breaks, what is the fallout? Are you left in space sticking your thumb out, hoping for a ride, or did you disappear into an alternate dimension, never to be heard from again? Or do things simply go boom?

And finally, is there anything that makes this particularly special? What makes it distinct from all the other go-go-go gadgets in the spacelanes? Is it man-made, a natural phenomena, or a gift from the ancients?

So, I hope you’ll tune in over the coming few weeks as I pop the hood on various starships and take a look at the story mechanics inside.

You’ve just been given the keys to your own FTL explorer ship… what do you do? This is a thought experiment that borders on wish fulfillment, but the kid in me thinks that’s the best kind. For all the flaws of the Star Trek prequel series Enterprise, it at least had some fun playing around with the “explore new worlds” part of the mission, and I really enjoyed those episodes.

So let’s play around with it some ourselves. Assume we’ve reached the level of space technology where we’ve set up a few permanent outposts throughout the solar system, and we’re able to build some reasonable spacecraft for scooting around the neighborhood. Then suddenly, FTL goes from a surprising theoretical possibility to an even more surprising engineering reality.

The NX-01 Enterprise rolls off the line, then the NX-02, and so on. They go off and take snapshots on Rigel-4 and draw lots to see who gets the next red shirt.

Meanwhile, you get a much more boring assignment on the exciting starship Survey-4. While those dashing captains check out the Top 40, you get to fill in the gaps, and there are some pretty big gaps. Within 100 light years, there are about 15,000 stars. Within 500 light years, there are almost two million. So if we’re going to be jetting around at warp 7, then there’s a lot of stuff between here and Rigel. (Approximately 850 light years, in fact.)

So where do you even start on an assignment like this? Let’s assume we got called in early on the project, so we can help lay out the scope of the mission. That is, what are we looking for? What do we need to find it? Where are we going to look? And just how long is this going to take?

We’re probably looking for life or at least places we could live, and from that we can narrow the scope a little bit, since not all stars are likely to support life as we know it. However, we’re probably also looking for useful resources, points of scientific interest, and staging points for further exploration. As such, we probably want to at least stop off at each star and give a quick look around.

What do we want from that quick look around? Personally, I’d want to know if there were any planets, and if so, how many? And if any of them seemed interesting, i.e. in the habitable zone, have big moons, or simply look pretty, I’d want an orbital survey on them.

Finding the inner planets will be easy enough by their reflected light. We found most of the ones in our solar system without even the aid of a telescope, simply because of the motion of planets against the background of otherwise static stars. The actual motion of the planets may not help us here, since waiting for Uranus or Neptune to move an appreciable fraction of their orbits can take a while.

However, the apparent motion of the planets will help us a lot. When an Earth-bound observer sees Saturn move against the stars, some of that motion is truly the motion of Saturn, but some of it is also the motion of Earth. As the Earth bounces back and forth from one side of the sun to the other, the viewing angle to Saturn swivels back and forth. In many cases, it appears as though it has reversed its orbital course, but it’s really just our own movement around the sun causing that motion. (This is what people mean when they say a planet is “in retrograde”, just that the relative motion of Earth and the planet makes it look like it’s going backwards.)

Well, in our nifty FTL survey ship, we should be able to bounce around in much less than the year Earth takes. The idea is to take a high resolution picture of the stellar system with our camera pointed towards a fixed location, like good old Sol, and when I say high-resolution, I’m thinking about stitching together a few thousand telescopic snapshots. Then move over a billion kilometers to the left, aim this camera array towards Sol, and take another picture. The position of the stars should stay more or less the same. Anything that appears, disappears, or moves from one picture to the next is probably local. (Or maybe some distant pulsar is just dicking with you.) If you do this from two or three directions, you should get a pretty good map of the inner planets.

It might not get you some of the outer planets. Neptune and Pluto were not originally discovered by telescope but by their gravitational interactions with Uranus. However, assuming better telescopes, no atmospheric interference, and better image processing than the eyes of early 20th century astronomers, we would probably find anything down to Pluto’s brightness. Whether or not we’d see something like Eris out in the Kuiper belt is more speculation than I’m willing to make right now.

So, what do we do with these planets once we’ve found them? As much as I’d love to send down some red shirts (and maybe even some people in them) to explore, an initial survey such as this should probably limit itself to space-based observations.

Telescopic observations can tell us a fair amount from a distance, but mostly that information can be used to rule out some planets from a more detailed survey. Spectrum absorption lines can tell us a lot about atmospheric makeup, and we can also measure the temperature to some degree. If it’s 200 degrees (or -200), then we’re probably not going to find life or suitable colony locations on it. I think we can also get a moderate idea of the atmospheric depth via telescope, since we knew of Mars’ minimal atmosphere years before we sent probes. (Though I confess, the science for extracting that info is beyond me.)

But if the atmosphere and temperature look appealing, it might be time for a much closer look. Just how much of a look can we actually take from space? I’ll take a stab at that next week.